Drafting instrument



June 6, 1939. A. E. SHAW DRAF'TING INSTRUMENT Filed April 8, 1938 JZZi/Skazz' 1N VEN TOR.

ATTORNEYS.

Patented June 6, 1939 UNITEDI'STATES PATENT OFFICE 4 Claims.

This invention relates to drafting instruments such as straight edges or guides, adjustable parallels, T-squares, triangles, French curves, etc.

Heretofore considerable difficulty has been experienced in keeping instruments of this type in proper position on a drafting board or on paper because they slip readily on the smooth surfaces contacted thereby.

An object of the present invention is to provide the instrument with surface gripping areas which will serve to prevent the instrument from slipping along the surface but at the same time will allow it to be lifted readily therefrom.

It is a further object of the invention to pro- 'vide anti-slipping means which can be incorporated readily in a drafting instrument of any of the kinds mentioned without materially altering its construction or appearance.

With the foregoing and other objects in view,

which will appear as the description proceeds, the

invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being understood that changes in the precise embodiment 5 of the invention herein described, may be made within the scope of what is claimed, without departing from the spirit of the invention.

In the accompanying drawing preferred forms of the invention have been shown.

30 In said drawing:

Figure 1 is a plan View of an adjustable parallel provided with the present improvement.

Figure 2 is a section therethrough on line 22 Figure 1.

5 Figure 3 is a bottom plan view of a straight edge equipped with the improvement.

Referring to the figures by characters of reference, l designates a straight edge which, in the structure shown in Figure 1, cooperates with an- 40 other straight edge 2 to form a parallel, the two straight edges being joined by pivoted links 3 which can be of flexible material if desired. In this structure the member I, which is formed of any suitable material, is provided at any suitable 4.5 point with transverse slots 4. These can be located close together adjacent to the center of the straight edge as shown in Figure 1. Obviously L instead of extending the slots perpendicularly to the longitudinal edges of the member, they can be 50' arranged at any other desired angles. Furthermore they can be disposed at any desired distances apart. Fitted within the slots 4 is a tape 5 having an adhesive coating on one side, this tape being preferably of the type known com- 55 mercially as Scotch drafting tape. The tape is arranged with its adhesive surface facing downwardly. Thus when the tape is threaded through the slots 4, the end portions thereof will adhere to the top surface of the member I so that portion of the tape between the slots will have its adhesive surface exposed. Thus when the member is placed on a drawing board or on a sheet of paper, the exposed adhesive portion will grip the surface to which the device is applied and therefore prevent the member I from slip- 10 ping along the surface. However it is possible, by exerting a lifting action on the member, to readily disengage the adhesive material from the surface thereunder engaged thereby so that the member thus can be brought to any other desired 15 position. In sliding this member from one position to another it can be tilted transversely so as to lift the adhesive from contact .with the surface thereunder and enable the member to slide along that edge thereof contacting with the supportgo ing surface.

The member 2 joined to the member I is also provided with one or more strips of tape indicated at 6 and these are likewise threaded through pairs of slots 1 so that the adhesive on the end portions of the tape will adhere to the top surface of the member 2 while the adhesive on that portion of the tape between the slots will be exposed for engagement with a drawing board or a sheet of drawing paper thereunder.

Obviously the same improvement can be applied to other kinds of drafting instruments. For example, and as shown in Figure 3, it can be applied to a straight edge 8 having slots 9 through which the tape I0 is extended, the adhesive surface ll of the tape being exposed under the straight edge and between the slots.

Importance is attached to the fact that the tape used is very thin but durable and that it is necessary to provide an adhesive only on one surface for the purpose of attaching the tape to the instrument and also leaving a portion for engagement with the surface on which the instrument is resting. Of equal importance is the feature of replenishability, whereby as the portion of the adhesive which adheres to the surface on which the instrument is resting begins to lose its adhesive properties after long usage, the two ends of the tape which are attached to the instrument are lifted and the tape is slid through the slots, thus providing a fresh area of adhesive for engagement with the surface to which the device is attached. There are no bulky protruding parts which would interfere with the proper manipulation of the device.

By providing flexible links in a parallel construction such as shown in Figure 1, it is possible, while member 2 is anchored on a surface, to lift the member I and adjust it to other positions.

What is claimed is:

1. An instrument of the class described including a member having separate slots therein, and means for holding said instrument to the imperforate surface of a sheet of paper or the like, said means including a tape having an adhesive on one surface, said tape being threaded through the slots and the adhesive on the end portions of the tape constituting means for joining said portions to one surface of the member while the remaining portion of the adhesive is exposed between the slots adjacent to the other surface of the member. 7

2. A drafting instrument or the like including a member having a pair of slots therein spaced from the edges thereof, and a tape threaded through, the slots, said. tape having an adhesive on one surface constituting means for attaching the end. portions of the tape to onev side of the member while the remaining portion of the adhesive is exposed between the slots and at the other side of. the member, said tape being of such length as to permit longitudinal. adjustment of the tape relative to the slotted member, thereby to bring a previously unexposed portion of the adhesive surface into exposed position.

3. A drafting instrument or the like including a member having a pair of slots therein spaced from the edges thereof, and a tape threaded through the slots, said tape having an adhesive on one surface constituting means for attaching the end portions of the tape to one side of the member while the remaining portion of the adhesive is exposed. between the slots; and.- at the other side of the member, the width of the tape being less than that of the member on which it is mounted. v

4 a drafting instrument, a pair of members, flexible link connections between the members, each ofsaid members having slots therein, said slots. beingdisposed in pairs, and a tape threaded through the slots of each pair, each tape having an adhesive on one surface constituting means. for affixing the. end portions. of the tape to one side. of the member onwhichit ismounted while the adhesive surface. of the. tape is exposed between. the slots. and. at the. other side of the member.

ALBERT EDWARD SHAW 

